1. Technical Field
The present invention relates to diaphragms of speakers, and more particularly, to a manufacturing method effective in adhering a stiffened plate and a base layer to each other tightly and shaping the stiffened plate and the base layer and to the diaphragm thus manufactured.
2. Description of Related Art
The recent development of smartphones is accompanied by a surge of research and development (R&D) of micro speakers. To enable speakers to generate sound which has satisfactory acoustic properties, a wide variety of diaphragm materials are being developed unceasingly. Some of the speakers are equipped with a composite diaphragm.
A conventional composite diaphragm manufacturing method involves: pre-shaping a base layer by a pressing process such that the base layer forms a central portion and a surround portion disposed along the periphery of the central portion; providing a stiffened plate; cutting the stiffened plate according to the dimensions and shape of the central portion; positioning the stiffened plate on the central portion; and adhering the stiffened plate to the base layer. After the stiffened plate and the base layer have been adhered together, the diaphragm has enhanced rigidity. Therefore, the diaphragm could provide optimal acoustic performance, and better high frequency sensing.
However, during the conventional composite diaphragm manufacturing process, the stiffened plate must be aligned with the central portion of the base layer in order for the stiffened plate to be adhered to the central portion snugly. However, in doing so, not only is the manufacturing process becomes intricate, but the yield is also reduced. Moreover, the conventional manufacturing method is flawed with the tendency of a glue to be excessive or insufficient. A glue oversupplied is likely to overflow the stiffened plate and thus compromise the overall sensitivity of the diaphragm. A glue undersupplied predisposes the central portion and the stiffened plate to inadequate adhesion strength, thereby causing the stiffened plate to come off the central portion whenever the diaphragm vibrates vigorously.